The use of convergent side disks in two-dimensional, gas turbine engine exhaust nozzles is well known in the art. Examples of such side disks are described in U.S. Pat. Nos. 4,819,876; 4,690,329 and 4,753,392. During engine operation, each of the convergent side disks rotates freely about a fixed axis to position the convergent flap secured thereto.
Due to the intense heat of the engine exhaust gas passing through the nozzle, the convergent side disks must be cooled to prevent life reduction, or failure, of the side disk components. However, due to the rotating nature of the side disks, limited means and methods are available for supplying coolant to, and exhausting coolant from, the side disks.
In the past, attempts to cool convergent side disks have included using coolant supplied to the side disks to provide impingement cooling of the inner surface of a liner and film cooling of the gas path surface of the liner. In this scheme, the coolant is supplied through a supply conduit which is concentric with the side disk's respective axis of rotation, and the spent cooling air is exhausted through the liner into the engine exhaust gas flow to provide film cooling of the liner. Unfortunately, at certain engine operating conditions, coolant supply pressure at the liner is less than the prevailing static pressure of the exhaust gas, resulting in reduced cooling flow and/or aspiration of the hot exhaust gas through the liner, and liner temperatures that exceed liner material capabilities. Although the potential for such aspiration is inherent in the use of a perforated liner, the film cooling provided by the perforated liner has been considered necessary, as the impingement cooling alone was not effective enough to adequately cool the liner.